Self and Conscious Experience 167“9x6” b2726 Self and the Phenomenon of Life: A Biologist Examines Life from Molecules to Humanity8.2 Some Properties of Consciousness
In 1892 William James defined consciousness as a state of the mind
that has four characteristics: (1) it is totally private; (2) it is constantly
changing; (3) each momentary state of consciousness is continuous with
the preceding and the following ones; (4) the content is focused and
selective for each person. This is known as the “stream of consciousness”
because it is analogous to flowing water.^10 I shall briefly review these
points, with new insights added whenever appropriate.
First, consciousness cannot be observed directly. It can only be
inferred from the behavior of an animal, from the workings of the brain, or,
in the case of humans, from testimony. In dealing with consciousness,
certain empathic influence from the observer cannot be avoided. For
this reason, psychology can never be as impartial a science as physics
and chemistry.
Next, consciousness has content, which is constantly changing. At the
most basic level, the content is made up of sense data, which organize to
form recognizable structures of the world. During our waking hours, some
sort of image always stays in our mind. When we open our eyes, the image
is usually that of the immediate outside world. But once the eyes are
closed, some image lingers on, which may or may not correspond to what
we just perceived — it could be an image of the past or one we imagine.
One of the properties of consciousness is its intensity, or focus of
attention. A global but diffuse consciousness can be likened to a room
illuminated by a light bulb, whereas intensified consciousness acts like
a searchlight, focusing on one spot or scanning left to right. The neuro-
physiological basis of focusing is the selective facilitation of sensory input
on one particular channel, while simultaneously inhibiting all others.^11
Consciousness is energy consuming.^12 Therefore, it is economical
for an organism not to pay attention to all details of the environment.
Habits are formed to convert useful action into automatism, and habit-
uation is developed to ignore repetitious innocuous stimuli, both being
energy conserving. Consciousness can sometimes be compared to a
landscape partially under water. What we are aware of is the part above